1. Which of the Following Is NOT True for Electromagnetic Waves

1. Which of the following is NOT true for electromagnetic waves

(a)they consist of changing electric and magnetic fields

(b) they travel at different speeds in vacuum, depending on their frequency

(e)they can be reflected

2.An electromagnetic wave is generated by (a) any moving charge

(b) any accelerating charge(c) only a charge with changing acceleration

(d) only a charge moving in a circle(e) only a charge moving in a straight line

3.For linearly polarized light the plane of polarization is

(a) perpendicular to both the direction pf polarization and the direction of propagation

(b) perpendicular to the direction of polarization and parallel to the direction of propagation

(d) parallel to both the direction of polarization and the direction of propagation

(e) none of the above

4.A clear sheet of Polaroid is placed on top of a similar sheet so that their polarizing axes make an angle of 30o with each other. The ratio of the intensity of emerging light to incident unpolarized light is

(a) 1:4(b) 1:3(c) 1:2(d) 3:4(e) 3:8

5.As light goes from one medium to another, it is bent away from the normal. Then

(a) the speed of the light has increased

(b) dispersion must occur(c) no change in speed has occurred

(d) the second medium has a higher index of refraction than the first

(e) refraction has not occurred because refraction means a bending toward the normal

6. The critical angle for total internal reflection at a diamond-air interface is 25o. Suppose light is incident at an angle  with the normal. Total internal reflection will occur if the incident medium is (a) air and= 25o

(b) air and  > 25o(c) air and < 25o (d) diamond and  > 25o

(e) diamond and  < 25o

7. An object is 2 m in front of a plane mirror. Its image is

(a) virtual, inverted, and 2 m behind the mirror

(b) virtual, inverted, and 2 m in front the mirror

(d) real, erect, and 2 m behind the mirror(e) none of the above

8.A light bulb burns in front of the center of a 40 cm wide plane mirror that is hung vertically on a wall. A man walks in front of the mirror along a line that is parallel to the mirror and twice as far from it as the bulb. The greatest distance he can walk and still see the image of the bulb is (a) 20 cm (b) 40 cm

9.An erect object is in front of a convex mirror a distance greater than the focal length. The image is (a) real, inverted and smaller than the object

(b) virtual, inverted, and larger than the object

(d) real, erect and larger than the object

(e) virtual, erect, and smaller than the object

10.As an object is moved from a distant location toward the center of curvature of a concave mirror its image (a) remains virtual and becomes smaller

(b) remains virtual and becomes larger(c) remains real and becomes smaller

(d) remains real and becomes larger (e) changes from real to virtual

11.An erect object is located on the central axis of a spherical mirror. The magnification is -3. This means (a) its image is real, inverted and on the same side of the mirror

(b) its image is virtual, erect and on the opposite side of the mirror

(d) its image is real, inverted and on the opposite side of the mirror

(e) its image is virtual, inverted and on the opposite side of the mirror

12.A concave refracting surface is one with the center of curvature

(a) to the left of the surface(b) to the right of the surface

(e) on the side with the higher index of refraction

13.A convex spherical refracting surface with radius r separates a medium with index of refraction 2 from air. As an object is moved toward the surface from far away along the central axis, its image

(a) changes from virtual to real when it is r/2 from the surface

(b) changes from virtual to real when it is r from the surface

(d) changes from real to virtual when it is r from the surface

(e) remains real

14.An erect object is 2f in front of a converging lens of focal length f. The image is

(a) real, inverted, magnified(b) real, erect, same size

(e) real, inverted, reduced

15. When an object is placed 20 cm from a diverging lens, a reduced image is formed. Which one of the following statements is necessarily true?

(a) the image is inverted(b) the image could be real

(d) the focal length of the lens may be less than 20 cm

(e) none of the above